Lubricating oil compositions containing novel amine-hydrocarbyl acid-orthophosphate-zinc halide complexes



United States Patent Oflflce 3,340,189 Patented Sept. 5, 1967 3,340,189 LUBRICATING OIL COMPOSITIONS CONTAINING NOVEL AMlNE-HYDROCARBYL ACID-ORTHO- PHOSPHATE-ZINC HALIDE COMPLEXES Frederic C. McCoy, Beacon, and Edwin C. Knowles, Poughkeepsie, N.Y., assignors to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Sept. 30, 1965, Ser. No. 491,822 11 Claims. (Cl. 252-325) The present invention relates to a novel amine complex of a hydrocarbyl substituted acid-orthophosphate and a zinc halide. The invention also relates to a lubricating oil composition containing the novel amine complex.

Developments in the gas turbine engine field have resulted in extensive efforts to formulate lubricating oil compositions having a high level of load-carrying properties in conjunction with low wear, rust protective properties and resistance to oxidation. From the many complexes prepared and tested, a new class of complex additives has been discovered which has outstanding properties in lubricating oil compositions and which promises to meet the stringent requirements of new and advanced gas turbine engines. In addition, these complexes provide substantial improvements in more conventional lubricants, such as gear oils, transmission fluids, automative greases and the like.

The novel complex of this invention is represented by the formula:

wherein R is an alkyl radical having from 6 to 24 carbon atoms, R is a hydrocarbyl radical having from 2 to 24 carbon atoms, R is hydrogen or a hydrocarbyl radical having from 4 to 24 carbon atoms, the sum of the carbon atoms in R and R" being in the range of to 30 carbon atoms, X is a halogen, a is a number from 1 to 2 and b is a number from 1 to 20. The preferred complex is one in which R is a tertiary alkyl radical having from 10 to 24 carbon atoms, R is an alkyl radical having from 4 to 12 carbon atoms, R" is hydrogen or an alkyl radical having from 4 to 12 carbon atoms, the sum of the carbon atoms in R and R" being in the range of 10 to 20 carbon atoms, X is a halogen, a is a number from 1 to 2 and b is a number from 4 to 20.

The complex is prepared by first reacting an amine with a hydrocarbyl acid orthophosphate compound until a substantially neutral amine salt complex is formed. The amount of the amine necessary depends on the number of free acid hydrogens present in the hydrocarbyl-substituted acid ortho hosphate. This invention is limited to complexes in which the orthophosphate has no more than two free acid hydrogens and accordingly 2 is the upper limit for the value of a. When a commercial mixture of hydrocarbyl acid orthophosphates is employed, the value of a can be between 1 and 2.

The substantially neutral amine salt is further reacted with a zinc halide to prepare the novel complex of the invention. The mole ratio of the amine salt complex to the zinc halide can range from 1:1 to 20:1 respectively although the preferred ratio for this reaction is in the range from about 4:1 to 20:1. The higher ratios of the amine salt complex to zinc halide provide outstanding stability in the formulated lubricating composition.

Amines which can be used for making the complex of the invention are the alkyl amines corresponding to the formula:

RHN

in which R is an alkyl radical having from 6 to 24 carbon atoms. The preferred amines are those in which R is a tertiary alkyl radical having from 10 to 24 carbon atoms.

Suitable amines include octylamines, laurylamine, octadecylamine, di-Z-ethylhexylamine, eicosylamine, tricosylamine, dimethyl dodecylamine, methyl octadecylamine and the like. Particularly preferred amines are certain commercially available mixtures of tertiary alkyl primary amines. A mixture of tertiary alkyl primary amines in which the alkyl radical comprises a mixture of alkyl groups having 11 to 14 carbon atoms is known as Primene 81-R. Another mixture of tertiary alkyl primary amines in which the alkyl radical comprises a mixture of alkyl groups having 18 to 24 carbon atoms is known as Primene JMT.

The hydrocarbyl acid orthophosphate component of the complex is represented by the formula:

in which R is a hydrocarbyl radical having from 2 to 24 carbon atoms, R" is hydrogen or a hydrocarbyl radical having from 4 to 24 carbon atoms, the sum of the carbon atoms in R and R" being in the range of 10 to 30. The preferred orthophosphate component is one in which R is an alkyl radical having from 4 to 12 carbon atoms, R is hydrogen or an alkyl radical having from 4 to 12 carbon atoms and the sum of the carbon atoms in R and R is in the range from 10 to 20.

Specific hydrocarbyl acid orthophosphate compounds which can be employed include isoamyl isooctyl acid o-phosphate, ethyl lauryl acid o-phosphate, di-isooctyl acid o-phosphate, ethyl oleyl acid o-phosphate, diphenyl acid o-phosphate, isoamyl 2-ethylhexyl acid o-phosphate, mono-stearyl acid o-phosphate, di-isoamyl acid o-phosphate and mono octylphenyl acid o-phosphate.

The inorganic component of the complex of the invention is a zinc halide represented by the formula ZnX in which X is a fluoride, chloride, bromide, or iodide ion. The fluorides and chlorides are the preferred halides for high load-carrying properties in the lubricating oil compositions.

Examples of specific complexes of this invention are listed below. In these examples the mole ratio indicated is the ratio respectively of the amine hydrocarbyl acid o-phosphate salt to the inorganic halide in the complex:

Primene JMT-Isoamyl isooctyl acid o-phosphate/zinc fluoride 13:1.

Primene 81-R-Isoamyl isooctyl acid o-phosphate/zinc fluoride 12:1.

TIicaprylylamine-Isoamyl isooctyl acid o-phosphate/zinc fluoride 13:1.

Primene JM-T-Isoamyl isooctyl acid o-phosphate/zinc chloride 13:1.

Primene JM-Tisoamyl isooctyl acid o-phosphate/zinc chloride 14:1.

Primene JMT'Mono-dioctyl acid orthophosphate/zinc fluoride 19:1.

Primene JM-T-Isoamyl isooctyl acid orthophosphate/ zinc fluoride 4: 1.

The following examples illustrate the preparation of the complex of the invention. The abbreviations TBN and TAN used in the examples refer to total base number and total acid number respectively.

EXAMPLE I 10,140 gm. 32.2 mol Primene JM-T (TBN=177) were charged to a stirred vessel. 6000 gm. of isoamyl octyl acid orthophosphate (TAN=301) were slowly added causing a temperature rise to about 40 C. 256 gm. (2.5 mol) of anhydrous zinc fluoride and 1200 ml. of water were added and the mixture heated to reflux for four hours. 2400 ml. of toluene were added and heated at reflux temperature to remove the water, following which the toluene was stripped off under vacuum using a nitrogen blanket. The Primene JMT-Isoamyl isooctyl acid o-phosphate/zinc fluoride complex (13.1 molar) analyzed as follows:

were charged to a vessel and reacted. Following the exothermic reaction, 20 ml. of water and 4.6 g. (0.045 mol) zinc fluoride were added and the mixture heated to reflux for 3 hours. 100 ml. of toluene were added and the mixture again refluxed to remove the water (20 ml. recovered). The product was filtered through Filter-Cel and stripped of toluene to a pot temperature of 140 C. using a stream of nitrogen. The final product, Weighing 225 g. in 99 percent yield, was a clear amber liquid. The molar ratio of alkyl ammonium phosphate to zinc fluoride was 12: 1.

EXAMPLE III 194. g. Primene JM-T (TBN=177) (.615 mol) were charged to a flask and 100 g. isoamylisooctyl acid orthophosphate added with stirring. (TAN of acid=343). The

reaction temperature rose from 27 C. to 70 C. Then 6.1

g. anhydrous zinc chloride (.045 mol) were added and the temperature of reaction raised to 100 C. Stirring was continued until no solid zinc chloride could be observed. The reaction mixture was cooled, diluted with 150 ml. benzene, filtered and the filtrate allowed to stand overnight on a steam plate to remove the benzene. The product was a clear amber viscous liquid. The molar ratio of alkyl ammonium phosphate to zinc chloride is 13.8: 1.

EXAMPLE IV 170 g. (0.54 mol) Primene IM-T (TBN=177) were charged to a flask and 100 g. isoamylisooctyl acid orthophosphate added with stirring. The temperature rose from 27 C. to 78 C. Then 13.9 g. anhydrous zinc fluoride (0.137 mol) and 60 ml. Water were added. The mixture was heated to reflux for 4 hours. Then 150 ml. of toluene were added and 60 ml. water removed by refluxing the toluene-water azeotrope. The toluene solution was filtered and stripped at a maximum temperature of 150 C. with nitrogen. The product (284 g.) was a clear, amber, viscous liquid.

Found, Theory,

Percent Percent Zn 3. 1 a. 1 F 1. 7 1. 8

The molar ratio alkyl ammonium phosphate to zinc fluoride is 4: 1.

EXAMPLE V The product (293 g.) was a viscous liquid molar ratio of 7 alkyl ammonium phosphate to zinc fluoride calculated to be 18.7:1.

The lubricating composition of the invention was prepared by blending in a conventional way a minor amount of the oil-soluble, load-carrying complex described hereinabove into a suitable lubricating oil base. Generally the complex is employed in an amount in the range of 0.05 to 10 percent by weight based on the weight of the lubricating oil composition with the preferred amount being from about 0.1 to 3 weight percent.

The base lubricating oil can be either a mineral lubricating oil or a synthetic lubricating oil. The mineral lubricating oil can be predominantly paraflinic or naphthenic or it can be a mixture of both types of mineral oils. Generally, the mineral oil will be a refined oil of predominantly paraflinic nature having a viscosity in the range from 30 to 150 Saybolt Universal seconds at 210 F.

Various types of synthetic lubricating oil bases can be employed for preparing the lubricants according to this invention. 'Aliphatic ester, polyalkylene oxides, silicones, esters of phosphoric and salicylic acid and the highly fluorine-substituted hydrocarbons can be employed. Examples of the aliphatic esters include di-(2-ethylhexyl) sebacate, the dialkyl azelates, dialkyl suberates, and the dialkyl adipates such as di-hexyl azelate, di-(Z-ethylheXyl) azelate, di-3,5,5-trimethylhexyl gluterate, di-(2-ethylhexyl) adipate, triamyl trica'rballylate', etc. The polyalkylene oxides include polypropylene oxide, polyisopropylene oxide diethcr, polyisopropylene oxide diesters, etc. The silicones include methyl silicone, methylphenyl silicone, and the silicates include tetraisooctyl silicate. The highly fluorinated hydrocarbons include fluorinated oil, perfluorohydrocarbons, etc.

Other effective synthetic lubricating oils include the neopentyl glycol esters such as the neopentyl glycol propionates, neopentyl glycol butyrates .and neopentyl glycol caprylates and the trimethylol alkanes such as trimethylol ethane, trimethylol propane, trimethylol pentane, trimethylol heptane, and trimethylol d'odecane and the like. Examples of the phosphate esters include tricresyl phosphate, trioctyl phosphate and tridecyl phosphate as Well as mixed aryl and alkyl phosphates.

The load-carrying and rust-resistant properties of lubricating oil compositions of the invention making them particularly suitable as gas turbine lubricants were deter- 1 mined by preparing a mixture of the complex in a synthetic lubricating oil. In the tests below, the formulated oil contained 1 percent by weight of the additive complex. The load-carrying property was determined by the Ryder Gear Test (Federal Test Method 6508). In thistest, the lubricant is employed to lubricate two spur gears in a Pratt and Whitney Gear and Lubricant Tester. The tester is operated at a gear speed of 10,000 r.p.m. using an oil inlet temperature of F. The load in the gear is increased in increments of 5 p.s.i. until 22.5 percent of the total tooth face area on the driving gear has been scuffed, the load applied in this run being considered the send load. The tooth load is then calculated in pounds per inch of tooth width.

The rust inhibiting properties of the lubricating oils were determined according to the well-known Humidity Cabinet procedure outlined in U.S. Military Specification MIL-L-21260 (corresponds to Federal Test Method Standard No. 791A, Method 5329).

The base oils employed in the preparation of gas turbine lubricating compositions were synthetic ester base oils. Base Oil A consisted of 96.6 percent by weight of a pentaerythritol ester plus the following additives: '1

Viscosity, cs. at 210 F. 4.93 Viscosity, cs. at 100 F 25.6 Viscosity, cs. at 40 F 7023 Flash, F. 490

Base Oil B was commercial synthetic ester consisting essentially of di-Z-ethylhexyl sebacate (Plexol 201-J).

GAS TURBINE LUBRICANTS Ryder MIL-L-21260 Rust Run Gear Test (24 Hr.)

Test, p.p.1.

2, 100 100% Rust. 2, 300 D0. t of 4, 240 Numerous spots. the complex of Example I. 4 Base Oil B+1% by weight of 4,400+ Numerous specks the complex of Example I. and spots. 5 Base Oil A+l% by weight of 4, 400+ Several large the complex of Example II. spots. fi Base Oil B+1% by weight of 4, 400+ 20% Rust.

the complex of Example III. 7 Base Oil B+0.25% by weight of 3, 266 the complex of Example IV. 8. Base Oil B+0.5% by Weight of 4, 120 the complex of Example IV. 9 Base Oil B+1.0% by weight of 4, 400+ the complex of Example V.

The improvement in the wear properties of a lubricating composition containing the complex of the invention was demonstrated in a gear oil formulation using the 4- Ball Wear Test. This test is conducted in a device employing four steel balls, three of which are in contact with each other in one plane in a fixed, triangular position in a reservoir containing the oil sample. The fourth ball is above and in contact with the other three. In conducting the test, the upper ball is rotated while it is pressed against the lower three balls, the pressure being applied by weights and a lever arm. The diameter of the scars on the three lower balls are measured by means of a low power micro scope. The average diameter measured in two directions on each of the three lower balls, is taken as a measure of the anti-wear characteristics of the lubricant.

The oil employed in this test was a mineral lubricating oil having an SUS viscosity at 210 F. of about 95. A commercial anti-wear agent of the sulfurized olefin type containing 46 percent sulfur was added to the mineral oil in the amount of 3 percent by weight of the composition and this composition was designated Base Oil C. The oil containing the complex of the invention also contained 1 percent by weight of an oil solution of a polymethacrylate resin. This polymethacrylate resin solution consisted of about 30 percent resin comprising 14 percent butyl, 12 percent hexyl, 42 percent lauryl and 32 percent stearyl methacrylate resins in the oil carrier. The methacrylate resin solution was added to the test oil solely to improve the viscosity of the oil and has no effect on the extreme pressure or load-carrying properties of the lubricating oil composition.

1 1 1112-40 kg.-l,800 r.p.m.200 F.

The anti-wear property of the base oil, which already possessed a high anti-wear property due to the presence of 3 weight percent of a commercial anti-wear additive, was surprisingly reduced more than half by the complex of the invention. This was a remarkable and unexpected improvement in the load-carrying properties of the mineral oil composition.

Obviously, other modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A lubricating oil composition comprising a lubricating oil and 0.05 to 10 percent by weight of a complex represented by the formula:

wherein R is an alkyl radical having from 6 to 24 carbon atoms, R is a hydrocarbyl radical having from 2 to 24 carbon atoms, R" is selected from the group consisting of hydrogen and a hydrocarbyl radical having from 4 to 24 carbon atoms, the sum of the carbon atoms in R and R being in the range from 10 to 30, X is a halogen, a is a number from 1 to 2 and b is a number from 1 to 20.

2. A lubricating oil composition comprising a lubricating oil and 0.05 to 10 percent by weight of a complex represented by the formula:

in which R is a tertiary alkyl radical having from 10 to 24 carbon atoms, R is an alkyl radical having from 4 to 12 carbon atoms, R" is selected from the group consisting of hydrogen and an alkyl radical having from 4 to 12 carbon atoms, the sum of the carbon atoms in R and R" being in the range of 10 to 20 carbon atoms, X is a halogen, a is a number from 1 to 2 and b is a number from 4 to 20.

3. A lubricating oil composition according to claim 1 in which X is the fluoride ion.

4. A lubricating oil composition according to claim 1 in which X is the chloride ion.

5. A lubricating oil composition comprising a lubricating oil and 0.05 to 10 percent by Weight of a complex having the formula:

wherein R is a tertiary C1844 alkyl radical, R is the isoamyl radical and R is the isooctyl radical.

6. A lubricating oil composition comprising a lubricating oil and 0.05 to 10 percent by weight of a complex having the formula:

wherein R is a tertiary C1144 alkyl radical, R is the isoamyl radical and R is the isooctyl radical.

7. A lubricating oil composition comprising a lubricating oil and 0.05. to 10 percent by weight of a complex having the formula:

wherein R is a tertiary C1844 alkyl radical, R is the isoamyl radical and R" is the isooctyl radical.

8. A lubricating oil composition comprising a lubricating oil and 0.05 to 10 percent by weight of a complex having the formula:

in which R is a tertiary C1844 alkyl radical, R is an octyl radical and R" is an octyl radical.

7 8 9. A lubricating oil' composition comprising'a lubri'at- References Cited having the formula: 1 2,863,904 12/1958 Cantrell et al. 252-325 3) (R'R 4)-]19 5 in which R is a ry 18-24 alkyl radical, i an octyl 3,256,188 6/1966 Papayannopoulos ef al;

5 3,080,222 3/1963 Cantrell'et a1 25232.5

radical and R" is an octyl radical. 252-42.7'

10. A lubricating oil composition according to claim 1 in which said lubricating oil is a mineral lubricating oil. DA IEL E, WYMAN, Primary Examiner.

11. A lubricating oil composition according to claim 1 in which said lubricating oil is a synthetic ester base 10 GARVLN ASSiSmm Examinerlubricating oil. 

1. A LUBRICATING OIL COMPOSITION COMPRISING A LUBRICATING OIL AND 0.05 TO 10 PERCENT BY WEIGHT OF A COMPLEX REPRESENTED BY THE FORMULA: 